Dipper tooth



" Nov. 18, 1941 P, v. LARSEN I 2,263,215

' DIPPER 'I'QO'IH Filed Nov. 9, 1940 I 2 sheets-sheet 1 2 Nov. 18, 1941.P. v. LARSEN DIPPER 'room Filed Nov. 9, 1940 2 Sheets-Sheet 2 vfaulvparaenl, m \Q Patented Nov. 18, 1941 DIPPER TOOTH Paul V. Larsen,Chicago, Ill., assignor to Pettibone Mulliken Corporation, a corporationof Delaware Application November 9, 1940, Serial No. 365,114

8 Claims. (Cl. 37-142 This invention is directed to a dipper tooth. Moreparticularly the invention is directed to the novel construction of thejoint between the dipper tooth and the stub upon the lip of the dipperbucket.

Generally dipper teeth are made of very hard materials such as manganesesteel, or alloy steel forgings. Teeth which constitute the diggingpoints of the dipper are, of course, subjected to much wear and greatstresses. Consequently they are made so that they can be replaced whenworn. Great dimculty is experienced in constructing a tooth which can beeasily made irom very hard steel alloys, and which can be connected tothe stub so that it remains tightly seated thereon despite the workingstress to which it is subjected, and at the same time can be easilyreplaced;

An object of this invention is to produce a connection between a dippertooth and its stub which achieves increased strength and wearingqualities by providing a greater than ordinary bearing area between theteeth and the stub.

Another object of the invention is to produce a connection between adipper tooth and its stub by means of which the dipper tooth canbefirmly and tightly seated upon the stub while at the same time the toothcan be easily replaced.

Another object of the invention is to produce a dipper tooth which is ofsimple construction and can be made with the minimumof machining andgrinding. Likewise the stub is of correspondingly simple constructionand can be produced with a minimum of machining and grinding.

Another object of the invention is to produce a novel key and slotconstruction for holding the dipper tooth to the stub.

Generally these objects of the invention are obtained by providing thedipper tooth point with opposed rearwardly diverging wings between whichprojects a shank of circular cross-section.

' This shank is adapted to be seated in a bore in the stub. The shank ofcircular section is flared into the dipper tooth body by means offilet-s which are tapered in plan, and the stub is shaped complementaryto the flare, thus providing an increase of bearing surface between thedipper tooth body and the stub over and above that obtained, forexample, by a shank of rectangular cross-section. The invention allowsthe stub to tie-constructed with plane surfaces on its top and bottom,and the bore for receiving the shank of the tooth is circular and easilymolded and ground out if desired. The inner sides of the wings can beformed with a wedge-like crosssection, and the stub complementarilyformed, so that the stub is locked against lateral displacement. The keyfor'fastening the tooth to the stub is brought very close to the toothbody and thus creates a stronger construction. The key itself is formedwith its opposing sides of equal radii, and the key slots in the shankand stub, respectively, each have one side of corresponding radii sothat a fully curvedsurface contact, rather than a line contact, isobtained between the key and the shank and the stub.

Generally the means by which the objects of this'invention are obtainedare more fully shown in the accompanying drawings in which: Fig. 1 is aperspective view of a'dipper tooth constructed according to thisinvention; Fig. 2 is an enlarged plan view of the dipper tooth of Fig.1; Fig. 3 is an enlarged side elevational view of the dipper tooth; Fig.4 is an end elevational view of the dipper tooth; Fig. 5' is aperspective view of the stub for receiving the dipper tooth; Fig. 6 isan enlarged plan view of Fig. 5; Fig. 7 is an enlarged side elevationalviewof the stub; Fig. 8 is an enlarged front elevational view of thestub; Fig. 9 is an enlarged side elevational view, partly in section,showing the connection between the dipp'er tooth and the stub;;,- Fig.10 is an enlarged perspective view of the key; and Figs. 11, 12 and 13are enlarged cross-sectional views, respectively, on the lines lll I,'29-: and I3--l3 of Fig. 9.

In Figs. 1 to 4, the dipper tooth or point A is. composed of a toothbody 2 and a shank 4.- Body 2 is wedge-shaped and has a solid forwardpoint 6 forming a cutting edge'irom which rearwardly extending divergingwings 8 extend, it being apparent that these wings converge forwardlyinto the solid body portion 6 to form in the body a V-shaped opening,curved.

The under surfaces of the wings may be flat the bight III of which isthe entire width of the tooth. The tooth illustrated has, however, anadditional feature in that the under surface of each wing is inclinedfrom the side of'the tooth to a median line 1, the inclination being ofthe order of 5 for a 4 inch point. These tapered surfaces coact withcomplementary surfaces on the stub to prevent sidewise movement of thetooth on the stub. This construction has the further advantage in thatthe tooth, when forged from an alloy steel, can be more readily removedfrom the die.

Shank 4 is of circular section, the diameter of which is less than theWidth of tooth A, and is composed of a portion l4 lying between wings 8,and of a tapered portion I2 which extends rearwardly of wings 8. Becauseof the convergence of wings 8 toward the cutting edge 6 of the tooth,the portion i4 of shank 4 is merged into the converging space by curvedfllets l6.

-. tact with wings 8 over a substantially U-shaped area, the outer edgeu being shown tapered in plan as indicated by dotted lines upon Fig. 2.By reason of this shape of the filets l6, shank 4 is firmly secured topoint 2, and substantially triangular surfaces 22 are created whichconstitute additional bearing areas for the resting of tooth A on stubB, over bearing surfaces achieved in prior art constructions. Of course,the under surfaces of wings 8 which lie laterally of shank 4 are alsoadapted to bear upon stub B, as is more extending making the tooth issymit is reversibly fully described later.

'Shank 4 has a longitudinal bore 24 therethroughfor the purpose of shankof lighter weight. As the metrical about its longitudinal axis,appliable to the stub. A keyhole fully described hereafter, extendsvertically through portion I 2 of shank 4 immediately to 1 the rear ofwings 8.

Stub B shown in Figs. 5 to 8, is of novel construction and is formed tocomplement the construction of tooth A. Stub B is composed of a bodyportion 30 adapted to be fixed to the dipper lip and is usually castintegral therewith, The tooth receiving end of body 30 is composed offorwardly converging plane surfaces 32 and 34 terminating in a roundedend portion 36 which has substantially the same radius as bight ID in'tooth A, the convergence of surfaces 32 and 34 j being the same as theconvergence of the inner surfaces of wings 8 of tooth A which form theV-shaped opening referred to above. A bore 38 having a larger diameterthan shank 4 to allow a loose fit of the shank in the bore, extendsinwardly from end 36 into the body 30 of stub B.

Because of the diameter of this bore, flanges 48 and 42 are formed,leaving the substantially U-shaped opening 46 in the end portion 01'stub B. When the tooth has the transversely inclined under wingsurfaces, stub B must be comple-' mentarily formed, and in accordancetherewith I] the bearing portions of surfaces 32 and 34, in-

cluding the surfaces of wings 40 and 42 are transversely inclined towardthe center as shown. From Figs. 5 and 6 it is clear that each flange 40and 42 provides a bearing area having a width :1: adjacent the bight 45of the U-shaped opening 46, said bearing area tapering toward the end36. The bight 45, of course, is the same width as end l5 of the tooth A.The plan of this hearing area corresponds to the bearing surface 22formed on the inner surface of each wing 8 by filets Hi. This bearingsurface represents'an increase in bearing area over and above that whichwould be produced from a shank of rectangular cross-section for tooth A,and a corre-- sponding rectangular bore in stub B, as such a rectangularsection, of corresponding strength, would leave flanges 40 and 42 with auniform 26, to be morewidth corresponding to the width of each end 36.

Stub B is further provided with a keyhole slot 48 which will bedescribed in detail later.

When tooth A is assembled with stub B, the shank 4 enters into bore 38(note Fig. 9) and fits loosely therein. The inwardly facing surfaces; 'gs fl gincludingfg tl surfaces 22, bear upo" riac'es of liahg'es ahd"42;" and the ends 36 of stub B are slightly spaced from the bight I0 oftooth A. Filets l6 on tooth A lie between flanges 48 and 42 on stub Band thus prevent tooth A from rotating on stub B. Because of theincreagad bearing surfaces between the tooth and the stub, the tooth isfurther pre vented from turning upon the stub, and is tightly heldthereon when a key is inserted through keyhole slots 26 and 48respectively. In addition, the transversely inclined under surfaces ofthe wings, and the complementarily shaped stub, as illustrated by theform of the inventio'n shown in the drawings, prevent sidewisedisplacement of the tooth upon the stub, thus greatlyreducing thepossibility of wear between the two.

Tooth A can be very easily cast, with a minimum of simple grinding, ifnecessary. Likewise stub B is very simply molded because of its fiatand/or planar upper and lower surfaces 32 and 34, and of the ease withwhich the bore 38 can be formed. "If the bore 38 is imperfectly cored itcan be easily ground out by means of a grinding wheel insertedtherein.As point A overlaps stub B and is tightly seated thereon, projectingportion I 2 of shank 4 need only be of a length sufficient to receivekey slot 26.

The novel key and keyhole construction is more fully shown in Figs. 9 to13, inclusive. The keyholes 26 and 48, respectively, are wedge-shapedwith sides y and y of small radius and sides z and z of larger radius.The radii of sides 1 and y are all equal, and likewise the radii ofsides 2 and z are equal, although this latter is not essential. The key50 shown in Fig. 10, is longitudinally tapered and-has its sides 52 and54 formed in a curve, the radius of which is equal to the radius ofsides 1/ and y of the keyhole slots. Consequently whenithe key isinserted into the keyhole slots, as shown in Figs. 9 and 11 to 13, thesides 52, 54 of the key will form a full surface contact, and willprovide a firm bearing connection with the keyhole slots. The sides aand z of the keyhole slots being of larger radius than the sides 1/ andy allow the key to be inserted into the keyholes without jamming andpermit the key to be seated in full surface contact with the sides 1/and 11'. Heretofore prior art key slots have had a larger radii and alarger width than the key and consequently the key only made a linecontact with the surface of the key slots. This permitted some lateralplay in the joint, which play caused gradually increasing wear upon thekey slot when the dipper was being operated. Increase of wear, ofcourse, means that the tooth becomes loose upon the stub and bendingstresses are introduced which lead to the failure of the tooth. Byreason of the novel key construction of this invention such loosening ofthe tooth is prevented because no play can take place in the key-andslot construction.

The means by which the objects of this invention are accomplished havingnow been de-,

scribed, I claim:

1. A dipper tooth construction comprising a wedge-shaped tooth havingforwardly converging spaced wings, a shank of circular section extendingfrom between said wings rearwardly thereof, filets uniting said shank tosaid wings, a stub complementarily shaped to said shank and fllets, andthat portion of said shank included between said wings being graduallytapered forwardly toward the'longitudinal axis of the said tooth.

2. Adipper. tooth as in claim 1, the contacting surfaces of the saidwings being inclined transversely toward the center line and taperingtoward the edges of the said wings, and'the stub contacting surfacesbeing inclined transversely toward and tapering inwardly to the saidcenter line.

3. A dipper tooth comprising a wedge-shaped point having a solid apexportion and two forwardly converging spaced wings, a shank of.circularsection extending between and rearwardly of said wings, and filetsuniting said shank to said wings, each filet being tapered in plan fromthe rear toward the front of the tooth with the rear portion of eachdiet being of substantially less width than the diameter of said shank.

4. A dipper tooth as in claim 3, said fllet having a width ofapproximately one-third the diameter of said shank at its rearmost end,and being tapered to awidth of approximately the diameter of said shanktoward the pointed end a width substantially equal to said diameter atthe forward edge of said shank; a stub having forwardly converging upperand lower plane surfaces complementary to the opening between saidwings, a bifurcated end portion complementary to said filets, and a borefor receiving said shank; said tooth being seated upon said shank withthe inner surfaces of said wings bearing upon said converging surfacesof said stub, said shank being fitted in said core, and said bifurcatedend embracing opposite sides of a portion of said shank.

6. A dipper tooth construction as in claim 5 furthercomprising key meansfor securing said shank to said stub. v

7. A key and slot construction for securing the shank of a dipper toothto a .stub comprising a key slot in said shank having one side curved ona relatively small radius and an opposite side curved on a relativelylarge radius, a second key slot in said stub having curved sides similarto those in said shank, but i'eversely positioned with respect to thesides in said shank, and a keyinserted into the aligned slots, said keyhaving two opposite sides curved the same as said relatively smallradius sides of the slots.

8. A key and slot construction for securing the shank of a dipper toothto a stub comprising wedge-shaped-and oppositely directed key slots insaid shank and stub, the smaller sides of said slots being similarlycurved, and a key inserted in said slots, said key having two opposedsides curved similar to the curve of said smaller sides in said slotswhereby the opposed sides of said key make a full surface contact withsaid smaller sides when said key is fitted in said slots.

PAUL V. LARSEN.

